It's how learners are taught to drive.Until a few months ago I was a driving instructor.
There's lots of stuff online about it - just search on google for "priority at crossroads".
Not sure what you're trying to say here but from your question, the black car has priority over the blue car, maybe if you explain what's happened you'd get the answer.
Yes, clearly there is an underlying reason why he wants this question answered and rather than skirting around the issue it will be a lot less painless for all of us if we are told why. @Crispness?
In this example the turn right rule does not apply to the Blue car as the yellow box isn't on a lane where the blue car is travelling in.The Blue car is crossing the oncoming lane (which has a yellow box for another purpose).
I'd imagine there was an accident, and you need to determine who was at fault?
Looking at your initial diagram, both blue arrows are the same thing, just different angles of joining the road.
As DOBLY says above, I don't believe the yellow box has any meaning for you in this instance.
Blue car should only pull out when when all 3 ways are clear.
Just a small correction. The blue car should only pull out when it is safe to do so and won't hinder or endanger other road users. That doesn't necessarily mean all 3 ways are clear data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7
Yes, I’m guessing the blue car and black car drove into each other.
And one of them is trying to lay blame on the other for entering the box when their exit wasn't clear?
Yes, that's exactly it. I would guess the OP is the one being blamed.
Looking at that diagram, presuming the rest of the road was clear, then the blue dotted line that gets you onto the correct lane first is the right one. The blue dotted line that turns at a sharp angle and has you going across a lot of the opposite lane is incorrect.
So the background is that the eastward-bound black vehicle was hit by the blue vehicle on the yellow box, although the way ahead was clear for the black vehicle.
Insurance offering 50:50. Personally I think black vehicle has a better case.